The present invention relates generally to power distribution, or junction box, assemblies. More particularly, the present invention teaches an improved power distribution assembly, particularly for use with a vehicle, in which high current input is distributed to both high and low current applications. The power distribution assembly is further expandable by the addition of an option end module and in order to increase the capacity of the system for higher end applications.
Existing power distribution systems and assemblies (or junction box assemblies) are known in the art, in particular those which employ a relatively few number of electrical bussing components necessary in inputting a high current load (such as originating from the vehicle electrical source) and stepping that current down to necessary output levels for subsequent application to various electrical components through a vehicle. Additional components of existing distribution assemblies include metal stamped frets, intentionally oversized to overcome the manufacturing and processing limitations of the metal stamped frets in the assembly process.
Printed circuit boards employed in the junction box assemblies often require increased circuit trace width or trace thickness (such as accomplished by increased plating thickness) in order to accomplish the higher current carrying capability demanded by the assembly, the result of which being an increase in the cost of the circuit board and/or the reduction in the number of circuits which can occupy the space available on the circuit board. Additionally, such existing assemblies exhibiting molded interconnect devices are limited to low and medium current applications. This is because, in order to apply the technology to high current applications, the circuits must be increased in cross sectional area, again compromising the number of such circuits which can occupy the area made available in the circuit board of the assembly.
Referring to the prior patent art, a first example of an electrical connection box is illustrated in U.S. Pat. No. 5,742,005, issued to Saka et al., and which teaches a first common circuitry component and a second specialty circuitry component. The common circuitry includes flat busbars, whereas the specialty circuitry includes a wire, longitudinal busbars or a flat circuit such as a flexible printed circuit or printed circuit board. A conductive layer is provided on which the common circuitry is formed, as is an additional conductive layer on which is provided the specialty circuitry. The circuitry components are arranged on over the other at different levels within a casing of the electrical connection box.
U.S. Pat. No. 5,703,757, issued to Hayes et al., teaches a junction box for motor vehicles in which first and second housing portions are provided for receiving and containing, respectively, low and high electrical current circuit boards. The housing portions extend in a generally common plane when connected together in order to form a housing unit. A planar insulating panel member containing buses and integral insulation displacement terminals is located between the housing portions and in a plane generally perpendicular to the common plane of the housing portions. The first and second housing portions are abutted and fastened together on opposed sides of the panel member with the buses and integral insulation displacement terminals. The displacement terminals are effective to directly receive insulated wires of an electrical harness and electrically connect the same to the buses and to circuits of and electrical components associated with the circuit boards.
U.S. Pat. No. 5,764,487, issued to Natsume, teaches an electrical junction block for an automotive vehicle having a housing containing a planar busbar and printed circuit board, these components being maintained in parallel and electrically insulated relationship to one another. Receptacles formed on the exterior surfaces of the housing receive mating electrical components such as fuses, relays and wiring harness connectors. Electrical connection between the printed circuit board and the electrical components is accomplished via a plurality of printed circuit boards oriented toward the busbar and second ends which pass through holes in the busbar and then through apertures in the housing and into the receptacles. Each printed circuit board connection terminal additionally includes spacer plates which maintain the printed circuit board in busbar a desired spaced distance, as well as a spring portion which makes electrical contact with the printed circuit board, deflecting slightly when the spacer plates are urged into contact with the printed circuit board.
Kasai, U.S. Pat. No. 6,116,916, teaches another variant of an electrical connection box incorporating a busbar and a printed circuit board, in turn having electronic devices mounted thereon and provided as internal circuits in a casing of the connection box. Terminals provided in the busbar are inserted through the printed circuit board to be secured to a conductive portion by solder for accomplishing a direct electrical connection.
Finally, U.S. Pat. No. 5,434,749, issued to Nakayama, teaches a hybrid printed circuit board for permitting connection between large and small current circuit conductors. An insulating substrate of synthetic resin is provided, having fixing bosses erected thereupon. A flexible printed circuit sheet is provided having small current circuit conductors and busbars as large current circuit conductors. The flexible printed circuit sheet is stacked and arranged on the insulating substrate so that the fixing bosses erected on the insulating substrate pass through and above the flexible printed circuit sheet. The busbars, as large current circuit conductors, are put in contact with the small current circuit conductors and the fixing bosses are heated and deformed to fix the busbars in place.
The present invention discloses an improved power distribution assembly, particularly for use with a vehicle, in which high current input is distributed to both high and low current applications. Among the numerous advantages and improvements provided by the power distribution assembly are included the flexibility to modify the electrical circuitry quickly and cost effectively, as well as easily adapting the assembly to multiple vehicle applications and to easily add on or interchange attachable electronic components.
Additional advantages include the ability to provide add on option content when required, such as is made possible by the addition of the option end module to increase the capacity of the system for higher end applications. Yet additional features include high and low current fuse protection and circuit splicing, provision of greater circuit density in a given area, and provision of multiple circuit bussing technologies best suited for individual applications within the unit and to provide reduced size and weight.
A housing of the assembly may be provided in a number of different configuration, on preferred arrangement including a lower housing and an engageable upper housing. The lower housing includes first, second and third pluralities of integrally formed socket portions, for receiving associated wire harness plugs, and corresponds to three differently sized and associated pluralities of male terminal output pins. External surfaces of the lower housing are further configured for receiving one or more spacing and mounting feet and in order to secure the housing assembly at any of a number of different mounting arrangements within or against a side wall of the vehicle engine compartment. The upper housing includes additional receptacle portions to communicate with opposite extending portions of each of the differently sized male terminal output pins and further provides for the attachment of existing electrical components include fuses, relays additional wire harness and the like.
A pair of high current upper and lower fuse busbars are provided and are engaged in electrically communicable fashion, such as by riveting, in sandwiching fashion and against opposite sides of a flexible circuit sheet, in turn typically wrapped about an insulating backing. Mini fuses, typically among those engageable with the upper housing, separately communicate with the upper and lower busbars through the flex circuit sheet and in order to step down and distribute the high current input (typically inputted from the vehicle electrical system).
The first, second and third pluralities of male output pins each again include oppositely extending upper and lower frets (or male pins), corresponding to the associated socket or receptacle portions of the lower and upper housings. The differently sized male output pins intercommunicate with the distribution side of the busbars, through the flexible sheet, and provide respective bussing levels (typically high, medium and low output current loads) for individual applications. In one preferred variant, the pluralities of output pins are provided in sizes of 6.3 mm, 2.8 mm and 1.5 mm, each corresponding to a different output current.
As also previously described, the add-on end module is easily engaged in both communicating fashion to the flex circuit and in secure mounting fashion to the assembled housing. In particular, the end module includes configured attachment portions for engaging an associated open side of the housing; an integrally molded flex circuit terminal of the end module pinching an electrically communicating end of the flex circuit against a corresponding flex circuit support within the lower housing. The end modules includes additional receptacle portions defined therein and for accommodating additional load outputs corresponding to yet additional terminal outputs associated with the end module. The power distribution assembly junction box) of the present invention is further configured for use either with or without the add-on end module and this is further facilitated by an attachable end plate, engageable over the open and exposed side of the main housing or, in the event the end (add on) module is engaged, over a corresponding open facing side of the end module.